PPT 2003 music, custom animation (ppt 2003)

I am doing a presentation with music in the background. I have the mp3 setup to play through 3 slides. The last element fades out on slide 1 and on slide 2 i have a picture fading in. The music, however, keeps playing for 5 or 6 seconds before switching to slide 2. I can't seem to make it go right to slide 2. I don't have this problem later on in the presentation, the slides goes one after the other through the music. I can't figure out why there is this delay and how to get rid of it. Any advice? thank you.